Received: 17 August 2020
Accepted: 31 July 2021
First Online: 24 August 2021
: This study was approved by the ethics committee at the University of Cologne and was therefore performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments. All persons gave their written informed consent prior to their inclusion in the study. The trial was registered at ExternalRef removed (DRKS00021518).
: not applicable.
: The authors declare that they have no competing interests.